The Harvard Indoor Track Revisited (page 4 of 4, the gun lap)
For a shoe midsole to behave like the time tested Harvard Indoor Track, this midsole would has to compress and release in perfect tune with the rise and fall of the peak body weight force. It would have to be a sole that remains stiff at impact but gradually, as the body weight force reaches it peak, compress. Specifically, the slope of the amount of compression and release of the midsole would have to be equal and opposite to the rise and fall of the peak body weight force (when injury causing forces are at their peak).
Designing a shoe sole that effectively gives and gives back would take a comprehensive understanding of how the body weight forces are naturally transferred under the foot and how those forces relate to the position of the rest of the body. It would take combining motion data with body weight force data to understand where and when peak stresses occur. And it would take studying gait in many individuals with varying foot and gait types across a number of conditions to understand natural force and movement patterns and to know which patterns are consistent and which are not. Those comprehensive biomechanical studies were never done 30 years ago. Only recently have we been publishing data that is informing what are these natural and consistent patterns.
I often wonder what Dr. McMahon would have to say about what we now know. He unfortunately passed away in 1999 and I never had a chance to talk to him about the new things we were just beginning to learn then about footwear. He was a brilliant scientist (and a novelist!). But it’s his success with the Harvard Indoor Track that is specifically noted in his obituary – that the track improved efficiency by 3% and reduced injuries by one-half. Powerful. And not forgotten.